Polycarbynes are polymers that can be used for the preparation of diamond-like carbon flints and in applications that require materials to withstand extreme conditions. Extreme conditions are conditions in which many materials typically fail or lose their structural integrity. Some examples of extreme conditions include extreme temperatures and pressures, high shear or tensile forces, and/or corrosive environments. Presently, metals, high performance plastics, diamonds and other high strength materials are used in many applications in which the materials are exposed to extreme conditions. However. these materials can be cumbersome, expensive and difficult to work with.
For example, diamond is used in and has been proposed for many applications in which materials that can withstand extreme conditions are needed. Diamond is a material from which cutting and drilling tools can be made. Diamond components could be ideal for use in car or jet engines. Diamond has been proposed for many electronic applications, such as the material from which microelectronic chips are made, because it has high mobility, a high breakdown strength, and a high radiation hardness. More specifically, diamond circuits could replace silicon circuits in many high performance applications, because diamond has a high resistance to damage from radiation, heat, chemicals and stress.
One advantage of using silicon in electronic circuits is that silicon can be "p-doped" or "n-doped" to tailor the properties of the electronic circuits to particular applications. To date, diamond has not been so easily "n-doped" or "p-doped". With the exception of a few experimental devices, researchers have so far succeeded in using diamond only as a supporting material in circuits made from conventional semiconductors, because they have been limited by the ability to achieve only one of the two main types of doping--"p-doping". "P-doped" diamond materials are those in which added impurity atoms (e.g., boron) attract electrons, creating mobile holes that conduct electricity. To make the equivalent of silicon devices, a technique for "n-type doping" diamond materials is also needed. In an "n-doped" material impurities that surrender some of their electrons (e.g. phosphorous) are used to make the material more conductive.
In addition to the inability to "n-dope" diamond materials, acquiring natural diamond can be very expensive and/or time consuming because of its scarcity and the difficulty with which it is mined. The difficulty of acquiring natural diamond has led to the need for development of synthetic diamond materials. Presently, there are several methods for preparing synthetic diamond materials. These methods include use of heat and pressure. chemical vapor deposition, and ultrasonically generated emulsions. Every year tons of commercially manufactured diamond materials are made by heating graphite to about 1370.degree. C. while subjecting it to about 50,000 atmospheres of pressure. This heat and pressure technique converts graphite's layered sheet-like atomic structure to diamond's three-dimensional tetrahedral crystalline network. This technique, however, is cumbersome and requires large and expensive machinery.
Chemical vapor deposition is a cheaper means of manufacturing synthetic diamond. In this process, carbon-containing gas gets decomposed, with microwaves or some other energy source, and the liberated carbon settles on a surface, such as glass or silicon. As the carbon settles, a thin film of solid diamond or diamond-like material develops. However, this film-forming process has not seen wide commercial success because it is very slow and difficult to control.
A recently developed method for preparing diamond-like materials was reported by Glenn T. Visscher et al. in Science, 260, 1496-1498 (1993). This method for preparing diamond-like materials involves transforming a liquid precursor into a synthetic diamond film. In order to achieve the transformation, .alpha.,.alpha.,.alpha.-trichlorotoluene is reduced in tetrahydrofuran, using an ultrasonically generated emulsion of a sodium-potassium alloy, to form poly(phenylcarbyne). The poly(phenylcarbyne) is then pyrolized to form a synthetic diamond material. This process is complex and requires a highly explosive alloy to form the intermediate poly(phenylcarbyne).
Using metal compounds to polymerize organohalides is not new in the art. U.S. Pat. No. 5,211,889 issued on May 18, 1993 to Reuben D. Rieke, specifically discloses examples of soluble highly reactive calcium reacting with dihalothiophenes and dihalobenzenes, for example, to form polymeric materials. However, there is no indication that carbyne-containing organohalides, such as .alpha.,.alpha.,.alpha.-trichlorotoluene, can form polycarbynes using the highly reactive calcium.
A need exists for a facile, relatively safe and inexpensive method of producing polycarbynes with reasonably high yields. A need also exists for a facile, relatively safe and inexpensive means of n-doping and p-doping polycarbynes. These facile methods should be readily adaptable to the production of a variety of polycarbyne materials. Once produced, polycarbynes, doped or non-doped, can be converted into synthetic diamond films, a plastic material, or other high strength material that maintains its structure in extreme conditions.